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Bernoulli’s Principle and Lift: How Airflow Helps Airplanes Fly

Updated: Dec 19, 2025

One of the most well-known explanations for how airplanes generate lift comes from Bernoulli’s Principle. Often introduced in early physics and aviation lessons, this principle helps explain the relationship between airspeed and pressure—and why an airplane wing can rise into the sky.


While Bernoulli’s Principle is not the only factor involved in lift, it plays an important role in understanding how airflow around a wing contributes to flight.



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What Is Bernoulli’s Principle?

Bernoulli’s Principle states that as the speed of a fluid increases, its pressure decreases. In aviation, the fluid we care about is air.


This means that faster-moving air exerts less pressure than slower-moving air. When air flows around objects like airplane wings, changes in airspeed lead to pressure differences—and pressure differences create forces.


The Shape of a Wing and Airflow

Airplane wings are designed with a special shape called an airfoil. Most airfoils are curved on the top and flatter on the bottom.


As an aircraft moves forward, air splits at the leading edge of the wing:

  • Some air flows over the top surface

  • Some air flows beneath the wing


Because of the wing’s curvature and angle, air traveling over the top surface speeds up. According to Bernoulli’s Principle, this faster-moving air has lower pressure. Meanwhile, the slower-moving air beneath the wing remains at higher pressure.

This pressure difference results in an upward force—lift.


Pressure Differences and Lift

Lift is produced when the pressure below the wing is greater than the pressure above it.

Bernoulli’s Principle explains how this pressure imbalance forms due to differences in airspeed.


The greater the difference in pressure:

  • The more lift the wing produces

  • The easier it is for the aircraft to climb or maintain altitude


Increasing airspeed increases the pressure difference, which is why airplanes must reach a certain speed before takeoff.


The Role of Angle of Attack

Wing shape alone is not enough to generate lift. The angle of attack—the angle between the wing and the oncoming airflow—also plays a critical role.


By tilting the wing slightly upward, the aircraft increases airflow speed over the top surface and strengthens the pressure difference. This allows even flat or symmetrical wings to produce lift, demonstrating that Bernoulli’s Principle works together with other aerodynamic factors.


Bernoulli Is Part of a Bigger Picture

It’s important to understand that Bernoulli’s Principle is not the only explanation for lift.

Another key factor is Newton’s Third Law of Motion, which states that for every action, there is an equal and opposite reaction.


As a wing deflects air downward, the air pushes back upward on the wing. In reality, lift results from a combination of:

  • Pressure differences explained by Bernoulli’s Principle

  • Downward deflection of air explained by Newton’s laws

  • Wing shape, speed, and angle of attack


Bernoulli’s Principle helps explain why pressure differences occur, but it works alongside these other effects.


Why Bernoulli’s Principle Matters in Aviation

Understanding Bernoulli’s Principle helps pilots and engineers:

  • Design more efficient wings

  • Predict how changes in speed affect lift

  • Understand stalls and slow-flight behavior

  • Improve aircraft performance and safety


It also helps students of aviation build a strong foundation in aerodynamics.


Conclusion

Bernoulli’s Principle provides a powerful insight into how airflow speed and pressure are connected. When applied to airplane wings, it helps explain how faster-moving air above the wing creates lower pressure, allowing higher pressure below to push the aircraft upward.


While it is only one part of the lift equation, Bernoulli’s Principle remains a cornerstone concept in understanding how airplanes fly.



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